We, the co-principal investigators, limit our practices to diseases of the retina and, as such, are intensively involved in the care of diabetic retinopathy. We have available and are using daily the equipment recommended in the Collaborative Diabetic Retinopathy Study protocol (2 Coherent Radiation Argon Lasers, 2 Zeiss Xenon Photocoagulators, and 3 Zeiss Fundus Flash II cameras with stereo separators). Trained technicians are presently operating this equipment and the necessary space is either already available or promised. The important contribution which we feel we can make to this study is a large volume of diabetic patients, previously not evaluated for diabetic retinopathy. The study has commitments from clinic directors and private practioners caring for over 6000 diabetic patients, who have expressed willingness to co-operate in this study. In addition, the principal investigators have an expanding diabetic retinopathy referral practice which is presently seeing 5 new patients with treatable diabetic retinopathy per week. The Wayne State University Department of Ophthalmology and Kresge Eye Institute is located in the still developing Detroit Medical Center. The Detroit Medical Center is a 250 acre area presently encompassing the WSU School of Medicine, 4 University affiliated hospitals (comprising over 2000 beds) and 2 medical research centers. The Detroit Medical Center is in the unique position of being the prime referral center in the Detroit Metropolitan Area, with a population exceeding 4 million. As a bonus, the Department of Ophthalmology, itself in the process of an expansion program and already the established retinal referral center in the metropolitan area has given this study a top priority commitment for the full period of the project.